Area of Rests of Malassez in Young and Adult Rat Molars: Evidences in the Formation of Large Rests

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Morphometrical analysis of cleaning capacity of a hybrid instrumentation in mesial flattened root canals

The cleaning capacity of hybrid and rotary instrumentation techniques in mesial flattened canals of mandibular first molars was evaluated by morphometrical analysis in this study. Twenty human mandibular first molars were randomly assigned into two groups, according to instrumentation technique, as follows: group 1, instrumentation with ProTaper Starter Kit (Dentsply/Maillefer) rotary system; group 2, manual instrumentation using K files (Dentsply/Maillefer) by crown-down technique in middle and apical thirds, cervical preparation with Gates-Glidden #1 and #2 (Dentsply/Maillefer) burs, and to finalise the preparation, ProTaper F2 and F3 rotary files. Serial transverse cross-sections (5 mu m) of the apical third, stained with hematoxylin and eosin, were analysed at 100 x original magnification. The images were submitted to morphometrical analysis with an integration grid to determine the percentage of root canal area with debris. Statiscal analysis (t-Student, P < 0.05) showed significant difference between the techniques (P < 0.05), although neither completely cleaned the root canal.

Response of mice connective tissue to intracanal dressings containing chlorhexidine

Substances containing chlorhexidine (CHX) have been studied as intracanal medicaments. The aim of the present study was to characterize the response of mouse subcutaneous connective tissue to CHX-containing medications by conventional optical microscopy. The tissue response was evaluated by implanting polyethylene tubes containing one of the substances evaluated: Calen paste + 0.5% CHX, Calen + 2% CHX, 2% CHX gel, and Calen paste (control). After experimental periods of 7, 21, and 63 days, the implants (n = 10) were removed along with the subcutaneous connective tissue. Tissue samples were subjected to histological processing, and sections were stained with hematoxylin and eosin. Qualitative and quantitative analyses of the number of inflammatory cells, blood vessels, and vascularized areas were performed. Results were analyzed by ANOVA and Tukey tests with the significance level set at 5%. We concluded that Calen + 0.5% CHX led to reparative tissue response in contrast with Calen + 2% CHX and 2% CHX gel, which induced persistent inflammatory response, pointing to the aggressive nature of this mixture. When Calen + 2% CHX and 2% CHX gel were compared, the latter induced more intense inflammatory response. Microsc. Res. Tech., 2012. (C) 2012 Wiley Periodicals, Inc.

Histochemical technique for the detection of chloride cells in fish

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Morphological changes in distant muscle fibers following thermal injury in Wistar rats

Purpose: Thermal injury causes catabolic processes as the body attempts to repair the damaged area. This study evaluated the effects of a scald injury on the morphology of muscle fibers belonging to a muscle distant from the lesion. Methods: Thirty Wistar rats were divided into control (C) and scalded (S) groups. Group S was scalded over 45% of the body surface, standardized by body weight. Rats in both groups were euthanized at four, seven and 14 days following the injury. The middle portions of the medial gastrocnemius muscles were sectioned, stained with hematoxylin and eosin and Picrosirius, and submitted to histological analysis. Results: Control group sections exhibited equidistantly distributed polygonal muscle fibers with peripheral nuclei, characteristic of normal muscle. The injured group sections did not consistently show these characteristics; many fibers in these sections exhibited a rounded contour, variable stain intensities, and greater interfiber distances. A substantially increased amount of connective tissue was also observed on the injured group sections. Conclusion: This experimental model found a morphological change in muscle distant from the site of thermal injury covering 45% of the body surface.

The Effects of a 785-nm AlGaInP Laser on the Regeneration of Rat Anterior Tibialis Muscle After Surgically-Induced Injury

Objective: This study aims to investigate the effects of low-level laser therapy (LLLT) on muscle regeneration. For this purpose, the anterior tibialis muscle of 48 male Wistar rats received AlGaInP laser treatment (785 nm) after surgically-induced injury.Background Data: Few studies have been conducted on the effects of LLLT on muscle regeneration at different irradiation doses.Materials and Methods: The animals were randomized into four groups: uninjured rats (UN); uninjured and laser-irradiated rats (ULI); injured rats (IN); and injured and laser-irradiated rats (ILI). The direct contact laser treatment was started 24 h after surgery. An AlGaInP diode laser emitting 75 mW of continuous power at 785 nm was used for irradiation. The laser probe was placed at three treatment points to deliver 0.9 J per point, for a total dose of 2.7 J per treatment session. The animals were euthanized after treatment sessions 1, 2, and 4. Mounted sections were stained with hematoxylin and eosin and used for quantitative morphological analysis, in which the number of leukocytes and fibroblasts were counted over an area of 4480 mu m(2). The data were statistically analyzed by analysis of variance (ANOVA) and the Bonferroni t-test.Results: Quantitative data showed that the number of both polymorphonuclear and mononuclear leukocytes in the inflammatory infiltrate at the injury site was smaller in the ILI(1), ILI(2), and ILI(4) subgroups compared with their respective control subgroups (IN(1), IN(2), and IN(4)) for sessions 1, 2, and 4, respectively (p < 0.05). on the other hand, the number of fibroblasts increased after the fourth treatment session (p < 0.05). With regard to the regeneration of muscle fibers following injury, only after the fourth treatment session was it possible to find muscle precursor cells such as myoblasts and some myotubes in the ILI(4) subgroup.Conclusion: During the acute inflammatory phase, the AlGaInP laser treatment was found to have anti-inflammatory effects, reducing the number of leukocytes at the injury site and accelerating the regeneration of connective tissue.

Clinical and histomorphometric characteristics of three different families with hereditary gingival fibromatosis

Objective. To examine the histomorphologic and histomorphometric features of tissue from 3 unrelated families with hereditary gingival fibromatosis (HGF).Study design. Twelve affected individuals from 3 HGF families and 3 control subjects were evaluated. Gingival samples were fixed in formalin and embedded in paraffin for hematoxylin and eosin stain to count the number of fibroblast and inflammatory cells. Sirius red staining was performed to quantitate the amount of collagen present.Results. Histomorphologic analysis of HGF showed extension of epithelial rete ridges into the underlying lamina propria and the presence of collagen bundles in the connective tissue. Analysis of the mean area fraction of collagen showed that there were significant increases in the collagen fraction for all HGF types compared with control subjects (P < .05). There were significant increases in the number of fibroblasts for HGFa and HGFb compared with control subjects (P < .05). The number of fibroblasts for HGFc were similar to that for control subjects.Conclusions. The collagen fraction was significantly greater in all HGF types compared with controls. The number of fibroblasts was significantly increased in 2 of the 3 HGF types compared with controls. These data indicate that different mechanisms may be responsible for tissue enlargement in different forms of HGF.

Reimplante mediato de dentes tratados ou não com solução de hipoclorito de sódio a 1% - estudo histomorfométrico em ratos

Foi avaliada a influência do hipoclorito de sódio a 1% no reparo do periodonto de incisivos reimplantados tardiamente em ratos. Os dentes foram mantidos em meio ambiente durante 30 minutos e a seguir imersos em hipoclorito de sódio a 1%, por 25 minutos. Os animais foram sacrificados aos 10, 30 ou 60 dias. Os cortes histológicos foram obtidos no sentido transversal dos terços cervical, médio e apical e delineados com um aumento de 52 vezes. Os eventos observados sobre a superfície radicular foram medidos quanto a sua extensão através de um sistema analisador de imagens (Mini-Mop, Carl Zeiss). Aos 10 dias, observou-se a predominância de tecido conjuntivo fibroso no grupo tratado. Aos 30 e 60 dias observou-se o aumento da anquilose e reabsorção por substituição, assim como neoformação limitada de ligamento periodontal. No grupo controle, aos 30 e 60 dias, foram observadas áreas de reabsorções mais extensas e profundas, quando comparadas ao grupo tratado. Os resultados possibilitaram as seguintes conclusões quando comparado o grupo tratado com o controle: a) leva à formação de tecido conjuntivo semelhante a uma cápsula fibrosa no período inicial do reparo; b) possibilita uma limitada neoformação de ligamento periodontal; c) ocasiona uma superfície de anquilose mais extensa; d) não impede a reabsorção por substituição.

Histologic study of use of microfibrillar collagen hemostat in rat dental sockets

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Histological study of the effect of some irrigating solutions on bacterial endotoxin in dogs

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Root canal adhesive filling in dogs' teeth with or without coronal restoration: A histopathological evaluation

The purpose of this study was to evaluate in vivo the response of the periradicular tissues after endodontic treatment and root filling with Epiphany/Resilon (Penntron Clinical Technologies, LLC, Wallingford, CT) or gutta percha and new Sealapex (SybronEndo, Glendora, CA) in dogs' teeth with or without coronal restoration. Teeth without coronal restorations were used to assess the influence of continuous exposure to the oral environment on the periradicular tissues. Sixty root canals with vital pulps in three dogs were instrumented and obturated in a single session and randomly assigned to one of four groups as follows. group 1: root canal filling with Epiphany/Resilon with coronal restoration, group 2: root canal filling with Sealapex sealer and gutta percha with restoration, group 3: root canal filling with Epiphany/Resilon without restoration, and group 4: root canal filling with Sealapex sealer and gutta percha without coronal restoration. After 90 days, the animals were euthanized, and the maxillas and mandibles were removed and submitted for histologic processing. Longitudinal sections were obtained and stained with hematoxylin and eosin, Mallory's trichrome, and Brown and Brenn stains and examined under light microscopy. There were significant differences found between the four groups (p < 0.05). The results showed that roots canals filled with Epiphany/Resilon, with coronal restoration, had significantly less periradicular inflammation than roots canals filled with gutta percha and Sealapex, with coronal restoration (p = 0.021). No significant difference was observed in the intensity of inflammation between roots canals filled with Epiphany/ Resilon with no restoration and roots filled with gutta percha and Sealapex with restoration (p = 0.269). Roots canals filled with gutta percha and Sealapex sealer without coronal restoration showed the greatest degree of periradicular inflammation.

A histologic assessment of the influence of low-intensity laser therapy on wound healing in steroid-treated animals

Objective: the aim of the present study was to evaluate the effect of low-intensity laser therapy on the wound healing process treated with steroid. Background Data: Various biological effects have been associated with low-level laser therapy (LLLT). Materials and Methods: Forty-eight rats were used, and after execution of a wound on the dorsal region of each animal, they were divided into 4 groups (n = 12), receiving the following treatments: G1 (control), wounds and animals received no treatment; G2, wounds were treated with LLLT; G3, animals received an intraperitoneal injection of steroid dosage (2 mg/kg of body weight); G4, animals received steroid and wounds were treated with LLLT. The laser emission device used was a GaAIAs (904 nm), in a contact mode, with 2.75 mW gated with 2.900 Hz during 120 sec (33 J/cm(2)). After the period of 3, 7, and 14 days, the animals were sacrificed and the parts sent to histological processing and dyed using hematoxylin and eosin (HE) and Masson trichromium (MT) techniques. Results: the results have shown that the wounds treated with steroid had a delay in healing, while LLLT accelerated the wound healing process. Also, wounds treated with laser in the animals treated with steroid presented a differentiated healing process with a larger collagen deposition and also a decrease in both the inflamatory infiltrated and the delay on the wound healing process. Conclusion: LLLT accelerated healing, caused by the steroid, acting as a biostimulative coadjutant agent, balancing the undesirable effects of cortisone (in the tissue healing process.

Sentinel node detection in cervical cancer with Tc-99m-phytate

Objectives. The aim of this study was to investigate the feasibility of sentinel lymph node (SLN) identification using radioisotopic lymphatic mapping with technetium-99 m-labeled phytate in patients undergoing radical hysterectomy with pelvic lymphadenectomy for treatment of early cervical cancer.Methods. Between July 2001 and February 2003, 56 patients with cervical cancer 1160 stage I (it 53) or stage 11 (it 3) underwent sentinel lymph node detection with preoperative lymphoscintigraphy (Te-99m-labeled phytate injected into the uterine cervix, at 3, 6, 9, and 12 o'clock, at a dose of 55-74 MBq in a volume of 0.8 ml) and intratoperative lymphatic mapping with a handheld gamma probe, Radical hysterectomy was aborted in three cases because parametrial invasion was found intraoperatively and we performed only sentinel node resection. The remaining 53 patients underwent radical hysterectomy with complete pelvic lymphadenectomy, Sentinel nodes were detected using a handheld gamma-probe and removed for pathological assessment during the abdominal radical hysterectomy and pelvic lymphadenectomy.Results. One or more sentinel nodes were detected in 52 out of 56 eligible patients (92.8%). A total of 120 SLNs were detected by lymphoscintigraphy (mean 2.27 nodes per patient) and intraoperatively by gamma probe, Forty-four percent of SLNs were found in the external iliac area, 39% in the obturator region, 8.3% in interiliae region, and 6.7),) in the common iliac area. Unilateral sentinel nodes were found in thirty-one patients (59%). The remaining 21 patients (4100 had bilateral sentinel nodes, Microscopic nodal metastases were confirmed in 17 (32%) cases. In 10 of these patients, only SLNs had metastases. The 98 sentinel node.,, that were negative on hematoxylin and eosin were submitted to cytokeratin immunohistochemical analysis. Five (5.1%) micrometastases were identified with this technique. The sensitivity of the sentinel node was 82.3% (CI 95% - 56.6-96.2) and the negative predictive value was 92.1% (CI 95% 78.6 98.3) the accuracy of sentinel node in predicting the lymph node status was 94.2%,Conclusion. Preoperative lymphoscintigraphy and intraoperative lymphatic mapping with Tc-99-labeled phytate are effective in identifying sentinel nodes in patients undergoing radical hysterectomy and to select women in whom lymph node dissection call be avoided. (c) 2005 Elsevier B.V. All rights reserved.

Influence of root canal dressings and sealers on repair of apical periodontitis after endodontic treatment

Objective. The objective of this study was to evaluate the histopathologic response of periapical tissues after root canal treatment of necrotic dog teeth with chronic apical periodontitis by using 2 calcium hydroxide-based root canal dressings and 2 root canal sealers.Study design. Seventy-eight root canals were instrumented by using 5.25% sodium hypochlorite as the irrigating solution, after which a calcium hydroxide paste (Calen/PMCC or Calasept) was placed for 30 days as a dressing. The root canals were then filled by using cold lateral gutta-percha condensation and an enclodontic sealer (Sealapex or AH Plus). After 360 days, the animals were killed by anesthetic overdose; then, the teeth were histologically prepared, sectioned, and stained with hematoxylin and eosin for optical microscopic analysis of apical and periapical tissue repair.Results. Statistical analysis showed that the poorest histopathologic results were observed in the Calasept/AH Plus group and that the Sealapex sealer overall resulted in better apical repair than the AH Plus sealer. The histopathologic results of Calen/PMCC paste with both AH Plus and Sealapex and Calasept paste with only Sealapex were statistically similar but were different from the results of Calasept with AH Plus.Conclusions. The results of this study in the dog showed differences in apical and periapical tissue repair of teeth with chronic apical periodontitis by using 2 calcium hydroxide root canal dressings and 2 sealers. More research is necessary to determine the best combination of dressings and sealers.

Effect of irrigating solution and calcium hydroxide root canal dressing on the repair of apical and periapical tissues of teeth with periapical lesion

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)